Octopus Pictures

    The octopus lives in many regions of the ocean, but particularly in coral reefs.  There are around 300 recognized species of octopus.  An octopus has eight arms, and those arms trail behind it as it swims in the ocean.  The majority of octopuses do not have an internal or external skeleton, and this enables them to squeeze through very tight spots.  An octopus does have a hard beak, and its mouth is in the center of the arms.  Octopuses are known to be very intelligent sea creatures.  In order to hide from their predators, octopuses will flee rapidly, hide, release ink, or even change their color to camouflage themselves.  All octopuses are venomous, but only the small-ringed octopuses have been found to be deadly to people.

     Each of the eight arms of the octopus have suction cups.  The majority of these sea creatures have soft bodies with no skeleton.  They do not have an outer shell or bones.  Their beak is the only hard portion of their body.  Being soft and flexible allows the octopus to squeeze through narrow areas in underwater rocks.  This ability assists them in escaping from predatory fish or morays. 

     Octopuses generally do not live long lives; in fact, some species only live for about six months, but some larger species may live as long as five years.  One major cause of death for octopuses is reproduction.  Interestingly enough, the males are only able to live a few months following mating.  Females of the species die a little after their eggs have hatched.  The females fast for about the month that they take care of their eggs, but their cause of death is not starvation; instead, the cause of death is from two optic glands that secrete endocrine.  If these glands are removed surgically, the octopus can continue to live beyond this point.

     An octopus does not have one heart, but three.  Two of the hearts are responsible for pumping blood through the two gills.  The third heart pumps blood throughout the octopus's body.  The blood of an octopus has a copper rich protein called hemocyanin, which helps transport oxygen.  This hemocyanin dissolves in the plasma rather than being carried within red blood cells, and the result is that the blood has a blue color.  The octopuses will bring water into their mantle cavity at which point it passes through the gills of the octopus. 

     Octopuses are considered to be extremely intelligent.  Experiments conducted with octopuses have shown that they have long-term and short-term memory.  The nervous system of the octopus is highly complex.   The eight arms of the octopus show reflex actions from three levels of the nervous system.  In experiments conducted in laboratories, octopuses have been trained to distinguish differences in patterns and shapes.  They have been able to practice observational learning. 

     The main defense of an octopus is to hide from predators to not be seen or to not be recognized as an octopus.  Other defenses used by an octopus is fast escape, use of inc sacs, autotomising limbs, and camouflage.  Most octopuses have the ability to eject a black ink in a big cloud to help them escape from predators.  The coloring agent in the ink is melanin.  An octopus's camouflage is supported by special skin cells which are able to change the color, reflectiveness, and opacity of the epidermis.  The chromatophores contain orange, yellow, brown, red, or black.  Most of the species have three of these colors, but some have two or four of the colors.  The ability to change colors can also be used to warn other octopuses.  The blue-ringed octopus will become bright yellow with blue rings when it becomes provoked.  The octopus can use its muscles in its skin to change the texture of its mantle to get a better camouglage.  The mantle is able to have the spiky appearance of seaweed in some species, and in others the bumpy texture of rock.  When an octopus is under attack, it has the ability to perform an arm autotomy, which means that it can detach its arm, and the result is that the crawling arm will be a distraction to other predators.  This is similar to how lizards and skinks can detach their tails.  There are some species, like the Mimic Octopus, who have a defense mechanism of using their flexible body and their ability to change colors to mimic other sea creatures that are more dangerous, such as the sea snakes, eels, and lionfish. 

     When the octopus reproduces, the males will use their specialized arm to insert packets of sperm in the the mantle cavity of the female.  This arm is called the hectocotylus, and it is typically the third right arm.  After mating, the males die after a few months of mating.  In some species, the female octopus has the ability to keep the sperm alive inside of her for weeks until her eggs have matured.  Once the eggs have been fertilized, the female octopus lays around 200,000 eggs.  These eggs are strung from the ceiling of her laire.  The female takes care of the eggs and guards them from predators.  She also blows currents of water over her eggs in order to give them enough oxygen.  During the month when she is taking care of the unhatched eggs, she does not hunt.  For sustenance, she may even ingest some of her own arms.  When the eggs hatch, she will leave and often is too weak to even provide a defense and is often killed.  The young octopuses will spend some time drifting in clouds of plankton and they feed on copepods, larval starfish, and larval crabs until they can go down to the bottom of the ocean. 

      Octopuses have a terrific sense of touch.  The suction cups found on the arms of the octopus have chemoreceptors so the octopus is able to taste what it is touching.  Octopuses move by swimming or by crawling.  Their fastest way of moving is through jet propulsion.  When they crawl, they walk on their arms, with many at once.  The octopus swims by pushing out a jet of water from a contractile mantle, and it aims it through a muscular siphon. 

     The largest octopus species is probably the North Pacific Giant Octopus.  The adults of this species usually weigh about 15 kg. or 33 lbs. with an arm span that reaches up to 4.3 m. or 14 feet.  The largest documented octopus was 71 kg. or 156.5 lbs.

     In many cultures, humans eat octopus.  The body parts are prepared in a number of different ways.  Octopus is common in Japanese foods, including takoyaki, Akashiyaki, and sushi.  In some small species, they are eaten alive.  Octopus is a popular dish in Hawaii too, and octopus is also a popular fish bait. 

    Some people attempt to keep octopuses as pets.  Often they will escape from "secure" tanks because they have mobility and very good problem solving skills.  Octopuses are also very strong for their small size.  Some species of octopus have even been known to kill species of sharks.